Self-reflection carbohydrate (Neil)

What I learned from today’s Biochemistry lecture is about carbohydrates. Carbohydrates are the most abundant biological molecules on Earth. It is an organic compound that consists of carbon, hydrogen and oxygen with hydrogen : oxygen atom ratio of 2:1. It has several key functions which include energy storage, structural components, cellular recognition and carbohydrate derivatives. Next, I learned about monosaccharides which are the basic carbohydrate units and are the simplest carbohydrates and cannot be hydrolysed to smaller carbohydrates under mild conditions. Important monosaccharides structures are such as glucose, fructose, ribose and glyceraldehyde. Monosaccharides also exhibit enantiomers, diastereomers and epimers characteristics. Moreover, I learned about Fischer projection which is a two dimensional representation for showing configuration of tetrahydral stereoisomers which monosaccharides often represented. In its ring forms, monosacharides are also known as shown as Haworth Projections. In Haworth Projections, monosaccharides can cyclize to form Pyranose, a 6-membered ring and Furanose, a 5-membered ring. When in the uncyclized form, monosaccharides act as reducing agents. 

            Furthermore, I have learned further more about carbohydrates that specifically focus on oligosaccharides and polysaccharides. Also, I learned about glycosidic bond. In carbohydrates, glycosidic bond is a linkage from the anomeric carbon to –OR group. Glycoside is a carbohydrate in which the –OH of the anomeric carbon is replaced by –OR. Those derived from pyranose are called pyranosides and those derived from furanose are called furanosides. Glycosides form between two monosaccharides forms disaccharides. 

            Other than that, I learned more about polysaccharides. Polysaccharides are formed from polymers of monosaccharides. There are two types of polysaccharides which are homopolysaccharides and heteropolysaccharides. Its functions include storage, structure and information. In terms of storage, there are three polysaccharides that functions as storage which are starch, glycogen and cellulose. Starch is the principal food reserve in plants. Next, glycogen is the storage polysaccharides in animal. Lastly, cellulose is a homopolymer which is a primary component of plant cell walls and green algae. In  terms of structure, there are two structural polysaccharides which are chitin which is the main componenet of cell walls of fungi and the exoskeletons of arthropods such as crustaceans and insects and glucoaminoglycans which are long unbranched polysaccharides made of repeating disaccharide units. Finally, glycoproteins are an example of information polysaccharides. Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. Glycoproteins are often important integral membrane proteins where they play role in cell-cell interactions. Generally, there are two types of glycoproteins which are O-linked glycoprotein and N-linked glycoprotein. 

            From this lecture, the first part of it is the basics of carbohydrates which have been learned since middle school. However, the second and final part of it is brand new to me which is fascinating to learn. Overall, I have learned so many things about carbohydrates and I am looking forward for the next lecture of Biochemistry.